diff --git a/rust/src/fileio_asyncio.rs b/rust/src/fileio_asyncio.rs
index d4affddf7..b9a060670 100644
--- a/rust/src/fileio_asyncio.rs
+++ b/rust/src/fileio_asyncio.rs
@@ -6980,11 +6980,18 @@ mod tests {
         assert_eq!(to_flush_now, 19);
         assert_eq!(zstd_result, 0);
 
-        state.codec_result = usize::MAX;
+        let mut error_state = ZstdCodecCallbackTestState {
+            pending_flush: 19,
+            codec_result: usize::MAX,
+            observed_input: None,
+            observed_output: None,
+            observed_directive: -1,
+        };
+        let error_cctx = (&mut error_state as *mut ZstdCodecCallbackTestState).cast::<c_void>();
         assert_eq!(
             unsafe {
                 fio_zstd_compress_stream_with(
-                    cctx,
+                    error_cctx,
                     0,
                     input.as_ptr(),
                     input.len(),